Can the following reaction occur? Why?
Cl2 + Mg 2 - 12 + MgCl2

yes

Magnesium (Mg) combines with chlorine (Cl2) to form a new product as magnesium chloride (MgCl2). Therfore its a combination reaction and the balanced equation can be written as: Mg(s)+Cl2(g)→MgCl2(s)

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.